The present invention relates to a device for measuring the breath of patients comprising measuring means arranged in a respiration conduit and provided with a sensor arranged in the air flow, the sensor being electrically connected with an electric and/or electronic circuit for holding its temperature on a constant value above the respiration temperature, a calorimeter unit measuring the current supply for compensating a momentary temperature decrease of the sensor because of the respiration air flow and a calculating and indicating device indicating the respiration air throughput in dependence on the current supply.
Known measuring devices of this kind have the disadvantage that the device cannot determine the flow direction of the respiration.
Therefore it is one object of the invention to provide a new measuring device which in a simple manner can decide whether the measured respiration dates belong to an expiration or an inspiration phase.
A further object of this invention is to provide a simple device having low-cost electronic circuits measuring the current supply for holding the sensor arrangement on a constant temperature level but indicating only the expiration phases of the patient.
A still further object of the invention is to provide a measuring device indicating the rate and the direction of a breath flow, the breath draw volume, the volume per minute, the inspiration and expiration periods and the breath frequency of respirated patients.